There have been some changes in the types involved. The object returned by Response/Request.getAttributes().get("org.restlet.http.headers") is a Series<Header>, not a Form, which is a Series<Parameter>. Because of type erasure, there is no runtime problem until the Restlet Engine tries to make use of the Parameter you stored and treat it as a Header.
You'll have to re-write your code to do something like this: ... import org.restlet.engine.header.Header; ... private static final String HEADERS_KEY = "org.restlet.http.headers"; ... @SuppressWarnings("unchecked") static Series<Header> getMessageHeaders(Message message) { ConcurrentMap<String, Object> attrs = message.getAttributes(); Series<Header> headers = (Series<Header>) attrs.get(HEADERS_KEY); if (headers == null) { headers = new Series<Header>(Header.class); Series<Header> prev = (Series<Header>) attrs.putIfAbsent(HEADERS_KEY, headers); if (prev != null) { headers = prev; } } return headers; } ... // In some method, what you originally wanted to do: getMessageHeaders(getResponse()).add("Access-Control-Allow-Origin", "*"); The use of putIfAbsent is probably overkill, since the only chance that another thread is modifying the attribute map is with asynchronous handling, but it can't hurt. --tim On Thu, Feb 9, 2012 at 2:54 PM, Michael Kaye <mik...@gmail.com> wrote: > Previous to the 2.0.11, I was able to set the responseHeaders as follows. > > > Form responseHeaders = (Form) > getResponse().getAttributes().get("org.restlet.http.headers"); > > if ( responseHeaders == null ) { > responseHeaders = new Form(); > > getResponse().getAttributes().put("org.restlet.http.headers", > responseHeaders); > } > responseHeaders.add("Access-Control-Allow-Origin", "*"); > > Now, I get the following runtime error, > > java.lang.ClassCastException: org.restlet.data.Parameter cannot be cast to > org.restlet.engine.header.Header > > How should I set response headers now? > > ------------------------------------------------------ > > http://restlet.tigris.org/ds/viewMessage.do?dsForumId=4447&dsMessageId=2920188 > ------------------------------------------------------ http://restlet.tigris.org/ds/viewMessage.do?dsForumId=4447&dsMessageId=2920205